This invention generally relates to steering knuckles for automobile suspension and steering systems, and in particular provides devices and methods that lower the chassis of an automobile.
A suspension system is an assembly of components designed to support a vehicle, and is typically configured so the weight of the vehicle is borne on the wheels and axles. The suspension system is designed to absorb or dissipate the effects of uneven road surfaces, and to keep the wheels properly aligned during straight-ahead driving as well as through turns.
In a rear wheel drive vehicle (RWD), the rear suspension system transfers power to propel the vehicle. The rear axle, or drive axle, is also called a live axle because it transmits power from the engine to the wheels. The front suspension system is intended to provide for directional control of the vehicle. The front axle, or steering axle, is referred to as a dead axle because it does not transmit power; the wheels passively rotate about the ends of the axle. In a front wheel drive vehicle (FWD) the front axle is a live axle, and the rear axle is a dead axle. In a four wheel drive vehicle (4WD) both the front and rear axles are live axles.
Many types of suspension systems include a steering knuckle. The steering knuckle helps to steer, brake, and support the automobile. When the driver turns the steering wheel, the tie rod transmits turning force to the knuckle, which turns the wheel in the desired direction. The knuckle also supports the brakes that transmit braking forces to the wheel. The weight of the vehicle is transmitted from the chassis, through the control arms, through the knuckle, and to the wheels.
In a conventional dead axle set-up, the steering knuckle includes a shaft-like projection, known as a spindle pin or spud, about which the wheel rotates. In contrast, a live axle steering knuckle does not have a spindle pin, but instead has a central aperture that accommodates the drive axle. The drive axle passes through the central aperture of the knuckle, and transmits power to the wheels. Thus, the wheel is actively rotated by the drive axle instead of passively rotating about the spindle pin.
There are known steering knuckle designs for lowering the chassis of an automobile. These designs are also called drop spindles, dropped spindles, or lowered spindles. In brief, the knuckle is modified such that the vehicle chassis frame is repositioned closer to the ground. It is relatively straightforward to modify a conventional dead axle steering knuckle to create a drop spindle. In contrast, there are significant difficulties in creating a live axle steering knuckle that operates as a drop spindle.
To accommodate for the knuckle aperture, others have proposed drop spindles that require inversion of the ball joints and A-frames. Such approaches can introduce strained geometries into the suspension, and result in suspensions having reduced travel. Further, they are cumbersome and inefficient, and can only be used on certain types of suspensions, such as coiled spring suspensions. More effective devices and methods are needed for lowering the chassis frame of an automobile, regardless of the type of suspension system used, while retaining a maximum amount of travel. The present invention satisfies such needs.